portion of the experimental farm is devoted
to a study of mustard meal.
MOSCOW, Idaho, posted August 2, 2005:
A University of Idaho student club – Soil Stewards
– is cultivating both a new crop of produce for
sale and an understanding of organic agriculture at
a UI experimental farm east of Moscow.
The students are working alongside UI soil scientists
in the College of Agricultural and Life Sciences, who
are exploring the nature of sustainability in organic
farming at the soil level and the potential of mustard
meal in achieving that goal.
This marks the third growing season for the club, which
includes about two dozen members from a wide range of
majors – from theater to business. “Some
members are more interested in learning how to grow
food, while others are more interested in research,”
said Jodi Johnson-Maynard, professor of soil science.
The research has resulted in numerous small independent
projects carried out by students through directed studies.
The plots also have been used for one senior’s
project and are currently the field site for a student
in the McNair fellowship program.
of Idaho student club Soil Stewards has succeeded
in getting fresh organic lettuce into their
dining halls mainly by growing it themselves.
The produce is also sold to Washington State
The club is selling shares in its community supported
agriculture program, or CSA. Subscribers pay the fee
up front, assuming some of the risk that goes with farming,
and receive in turn weekly supplies of fresh, organic
Last summer, the club sold 10 CSA shares. This year
it expects to produce enough to support 25 shares. The
10-week subscription costs $150.
The club also sells produce from a stand on campus
and delivers produce such as salad greens and basil
to Sodexho, which manages campus dining services. Johnson-Maynard
said prospects are good for expanding that relationship.
The proceeds from the produce paid for the use of three
acres and an elaborate irrigation system installed at
the Department of Plant, Soil and Entomological Sciences
Much of the club’s area is planted to organic
spring wheat to grind into flour, with another half
an acre of vegetables. Much of the garden is devoted
to variety trials, testing which kinds of tomatoes,
potatoes, eggplant and other vegetables grow best under
organic systems on the Palouse.
Another major portion of the plot is devoted to a study
of mustard meal as a soil amendment for organic farming.
“Mustard is a natural fit for us because of the
work other UI researchers have done, ranging from plant
breeding to biodiesel development,” Johnson-Maynard
The oils pressed from mustard, Canola and rapeseed
can either be used in diesel engines straight or converted
to biodiesel, a use that is attracting greater interest
with rising fuel prices.
The meal left over after the oil is pressed has attractions
of its own, Johnson-Maynard said. The cornflake-like
meal contains more nitrogen than most animal manures,
one of the most common organic fertilizers.
An elaborate irrigation system was installed at the farm to minimize water
That’s where the other research on the farm reaches
into the realm of high science. Experiments funded by
a $613,000 USDA National Research Initiative grant focus
on intriguing questions, such as why mustard meal appears
to release more nitrogen for plant use into the soil
than the meal alone contains.
The NRI team is tracking the path of nitrogen through
the soil. One promising result so far, Johnson-Maynard
said, is that the most common form of nitrogen found
after the meal is applied is ammonium, which is less
mobile than nitrates and less likely to contaminate
As for why more nitrogen appears to be freed up for
plants, another valuable property of mustard and its
kin appears to be in play, Johnson-Maynard said.
Glucosinolates are chemicals that give mustard its
zip. They also form new compounds that can kill weeds
or soil microbes, benefits that farmers of all persuasions
are learning to value.
The researchers suspect that the “extra”
nitrogen may come from microbes killed by the mustard
Exploring the benefits of mustard meal could help organic
farmers find new ways to fertilize and protect their
crops, aiding their survival, and their sustainability,
in the long run, Johnson-Maynard said.